Force textures to lowest MIP level and NULL fixed function / NULL PS1.x / NULL PS 2.x options are very useful for detecting bottlenecks of one or another Direct3D application as they can reduce the load on the texture units or replace pixel shaders of one or another version with NULLs in a given application. The reviewers trying to guess what factors limit performance of a certain benchmark will appreciate such solution.
Thirdly, this tab got rid of the Texel alignment slider for those video adapters which do not support it. We discussed this problem with the driver developers and we are glad they listened to us and removed this option for owners for NV20 and older chips